10edff03dSPeter Rosin // SPDX-License-Identifier: GPL-2.0 28f3addf1SPeter Rosin /* 38f3addf1SPeter Rosin * Multiplexer subsystem 48f3addf1SPeter Rosin * 58f3addf1SPeter Rosin * Copyright (C) 2017 Axentia Technologies AB 68f3addf1SPeter Rosin * 78f3addf1SPeter Rosin * Author: Peter Rosin <peda@axentia.se> 88f3addf1SPeter Rosin */ 98f3addf1SPeter Rosin 108f3addf1SPeter Rosin #define pr_fmt(fmt) "mux-core: " fmt 118f3addf1SPeter Rosin 128f3addf1SPeter Rosin #include <linux/device.h> 138f3addf1SPeter Rosin #include <linux/err.h> 148f3addf1SPeter Rosin #include <linux/export.h> 158f3addf1SPeter Rosin #include <linux/idr.h> 168f3addf1SPeter Rosin #include <linux/init.h> 178f3addf1SPeter Rosin #include <linux/module.h> 188f3addf1SPeter Rosin #include <linux/mux/consumer.h> 198f3addf1SPeter Rosin #include <linux/mux/driver.h> 208f3addf1SPeter Rosin #include <linux/of.h> 218f3addf1SPeter Rosin #include <linux/of_platform.h> 228f3addf1SPeter Rosin #include <linux/slab.h> 238f3addf1SPeter Rosin 248f3addf1SPeter Rosin /* 258f3addf1SPeter Rosin * The idle-as-is "state" is not an actual state that may be selected, it 268f3addf1SPeter Rosin * only implies that the state should not be changed. So, use that state 278f3addf1SPeter Rosin * as indication that the cached state of the multiplexer is unknown. 288f3addf1SPeter Rosin */ 298f3addf1SPeter Rosin #define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS 308f3addf1SPeter Rosin 318f3addf1SPeter Rosin static struct class mux_class = { 328f3addf1SPeter Rosin .name = "mux", 338f3addf1SPeter Rosin .owner = THIS_MODULE, 348f3addf1SPeter Rosin }; 358f3addf1SPeter Rosin 368f3addf1SPeter Rosin static DEFINE_IDA(mux_ida); 378f3addf1SPeter Rosin 388f3addf1SPeter Rosin static int __init mux_init(void) 398f3addf1SPeter Rosin { 408f3addf1SPeter Rosin ida_init(&mux_ida); 418f3addf1SPeter Rosin return class_register(&mux_class); 428f3addf1SPeter Rosin } 438f3addf1SPeter Rosin 448f3addf1SPeter Rosin static void __exit mux_exit(void) 458f3addf1SPeter Rosin { 468f3addf1SPeter Rosin class_unregister(&mux_class); 478f3addf1SPeter Rosin ida_destroy(&mux_ida); 488f3addf1SPeter Rosin } 498f3addf1SPeter Rosin 508f3addf1SPeter Rosin static void mux_chip_release(struct device *dev) 518f3addf1SPeter Rosin { 528f3addf1SPeter Rosin struct mux_chip *mux_chip = to_mux_chip(dev); 538f3addf1SPeter Rosin 548f3addf1SPeter Rosin ida_simple_remove(&mux_ida, mux_chip->id); 558f3addf1SPeter Rosin kfree(mux_chip); 568f3addf1SPeter Rosin } 578f3addf1SPeter Rosin 58a49c3feeSBhumika Goyal static const struct device_type mux_type = { 598f3addf1SPeter Rosin .name = "mux-chip", 608f3addf1SPeter Rosin .release = mux_chip_release, 618f3addf1SPeter Rosin }; 628f3addf1SPeter Rosin 638f3addf1SPeter Rosin /** 648f3addf1SPeter Rosin * mux_chip_alloc() - Allocate a mux-chip. 658f3addf1SPeter Rosin * @dev: The parent device implementing the mux interface. 668f3addf1SPeter Rosin * @controllers: The number of mux controllers to allocate for this chip. 678f3addf1SPeter Rosin * @sizeof_priv: Size of extra memory area for private use by the caller. 688f3addf1SPeter Rosin * 698f3addf1SPeter Rosin * After allocating the mux-chip with the desired number of mux controllers 708f3addf1SPeter Rosin * but before registering the chip, the mux driver is required to configure 718f3addf1SPeter Rosin * the number of valid mux states in the mux_chip->mux[N].states members and 728f3addf1SPeter Rosin * the desired idle state in the returned mux_chip->mux[N].idle_state members. 738f3addf1SPeter Rosin * The default idle state is MUX_IDLE_AS_IS. The mux driver also needs to 748f3addf1SPeter Rosin * provide a pointer to the operations struct in the mux_chip->ops member 758f3addf1SPeter Rosin * before registering the mux-chip with mux_chip_register. 768f3addf1SPeter Rosin * 778f3addf1SPeter Rosin * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno. 788f3addf1SPeter Rosin */ 798f3addf1SPeter Rosin struct mux_chip *mux_chip_alloc(struct device *dev, 808f3addf1SPeter Rosin unsigned int controllers, size_t sizeof_priv) 818f3addf1SPeter Rosin { 828f3addf1SPeter Rosin struct mux_chip *mux_chip; 838f3addf1SPeter Rosin int i; 848f3addf1SPeter Rosin 858f3addf1SPeter Rosin if (WARN_ON(!dev || !controllers)) 868f3addf1SPeter Rosin return ERR_PTR(-EINVAL); 878f3addf1SPeter Rosin 888f3addf1SPeter Rosin mux_chip = kzalloc(sizeof(*mux_chip) + 898f3addf1SPeter Rosin controllers * sizeof(*mux_chip->mux) + 908f3addf1SPeter Rosin sizeof_priv, GFP_KERNEL); 918f3addf1SPeter Rosin if (!mux_chip) 928f3addf1SPeter Rosin return ERR_PTR(-ENOMEM); 938f3addf1SPeter Rosin 948f3addf1SPeter Rosin mux_chip->mux = (struct mux_control *)(mux_chip + 1); 958f3addf1SPeter Rosin mux_chip->dev.class = &mux_class; 968f3addf1SPeter Rosin mux_chip->dev.type = &mux_type; 978f3addf1SPeter Rosin mux_chip->dev.parent = dev; 988f3addf1SPeter Rosin mux_chip->dev.of_node = dev->of_node; 998f3addf1SPeter Rosin dev_set_drvdata(&mux_chip->dev, mux_chip); 1008f3addf1SPeter Rosin 1018f3addf1SPeter Rosin mux_chip->id = ida_simple_get(&mux_ida, 0, 0, GFP_KERNEL); 1028f3addf1SPeter Rosin if (mux_chip->id < 0) { 1038f3addf1SPeter Rosin int err = mux_chip->id; 1048f3addf1SPeter Rosin 1058f3addf1SPeter Rosin pr_err("muxchipX failed to get a device id\n"); 1068f3addf1SPeter Rosin kfree(mux_chip); 1078f3addf1SPeter Rosin return ERR_PTR(err); 1088f3addf1SPeter Rosin } 1098f3addf1SPeter Rosin dev_set_name(&mux_chip->dev, "muxchip%d", mux_chip->id); 1108f3addf1SPeter Rosin 1118f3addf1SPeter Rosin mux_chip->controllers = controllers; 1128f3addf1SPeter Rosin for (i = 0; i < controllers; ++i) { 1138f3addf1SPeter Rosin struct mux_control *mux = &mux_chip->mux[i]; 1148f3addf1SPeter Rosin 1158f3addf1SPeter Rosin mux->chip = mux_chip; 1168f3addf1SPeter Rosin sema_init(&mux->lock, 1); 1178f3addf1SPeter Rosin mux->cached_state = MUX_CACHE_UNKNOWN; 1188f3addf1SPeter Rosin mux->idle_state = MUX_IDLE_AS_IS; 1198f3addf1SPeter Rosin } 1208f3addf1SPeter Rosin 1218f3addf1SPeter Rosin device_initialize(&mux_chip->dev); 1228f3addf1SPeter Rosin 1238f3addf1SPeter Rosin return mux_chip; 1248f3addf1SPeter Rosin } 1258f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_chip_alloc); 1268f3addf1SPeter Rosin 1278f3addf1SPeter Rosin static int mux_control_set(struct mux_control *mux, int state) 1288f3addf1SPeter Rosin { 1298f3addf1SPeter Rosin int ret = mux->chip->ops->set(mux, state); 1308f3addf1SPeter Rosin 1318f3addf1SPeter Rosin mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state; 1328f3addf1SPeter Rosin 1338f3addf1SPeter Rosin return ret; 1348f3addf1SPeter Rosin } 1358f3addf1SPeter Rosin 1368f3addf1SPeter Rosin /** 1378f3addf1SPeter Rosin * mux_chip_register() - Register a mux-chip, thus readying the controllers 1388f3addf1SPeter Rosin * for use. 1398f3addf1SPeter Rosin * @mux_chip: The mux-chip to register. 1408f3addf1SPeter Rosin * 1418f3addf1SPeter Rosin * Do not retry registration of the same mux-chip on failure. You should 1428f3addf1SPeter Rosin * instead put it away with mux_chip_free() and allocate a new one, if you 1438f3addf1SPeter Rosin * for some reason would like to retry registration. 1448f3addf1SPeter Rosin * 1458f3addf1SPeter Rosin * Return: Zero on success or a negative errno on error. 1468f3addf1SPeter Rosin */ 1478f3addf1SPeter Rosin int mux_chip_register(struct mux_chip *mux_chip) 1488f3addf1SPeter Rosin { 1498f3addf1SPeter Rosin int i; 1508f3addf1SPeter Rosin int ret; 1518f3addf1SPeter Rosin 1528f3addf1SPeter Rosin for (i = 0; i < mux_chip->controllers; ++i) { 1538f3addf1SPeter Rosin struct mux_control *mux = &mux_chip->mux[i]; 1548f3addf1SPeter Rosin 1558f3addf1SPeter Rosin if (mux->idle_state == mux->cached_state) 1568f3addf1SPeter Rosin continue; 1578f3addf1SPeter Rosin 1588f3addf1SPeter Rosin ret = mux_control_set(mux, mux->idle_state); 1598f3addf1SPeter Rosin if (ret < 0) { 1608f3addf1SPeter Rosin dev_err(&mux_chip->dev, "unable to set idle state\n"); 1618f3addf1SPeter Rosin return ret; 1628f3addf1SPeter Rosin } 1638f3addf1SPeter Rosin } 1648f3addf1SPeter Rosin 1658f3addf1SPeter Rosin ret = device_add(&mux_chip->dev); 1668f3addf1SPeter Rosin if (ret < 0) 1678f3addf1SPeter Rosin dev_err(&mux_chip->dev, 1688f3addf1SPeter Rosin "device_add failed in %s: %d\n", __func__, ret); 1698f3addf1SPeter Rosin return ret; 1708f3addf1SPeter Rosin } 1718f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_chip_register); 1728f3addf1SPeter Rosin 1738f3addf1SPeter Rosin /** 1748f3addf1SPeter Rosin * mux_chip_unregister() - Take the mux-chip off-line. 1758f3addf1SPeter Rosin * @mux_chip: The mux-chip to unregister. 1768f3addf1SPeter Rosin * 1778f3addf1SPeter Rosin * mux_chip_unregister() reverses the effects of mux_chip_register(). 1788f3addf1SPeter Rosin * But not completely, you should not try to call mux_chip_register() 1798f3addf1SPeter Rosin * on a mux-chip that has been registered before. 1808f3addf1SPeter Rosin */ 1818f3addf1SPeter Rosin void mux_chip_unregister(struct mux_chip *mux_chip) 1828f3addf1SPeter Rosin { 1838f3addf1SPeter Rosin device_del(&mux_chip->dev); 1848f3addf1SPeter Rosin } 1858f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_chip_unregister); 1868f3addf1SPeter Rosin 1878f3addf1SPeter Rosin /** 1888f3addf1SPeter Rosin * mux_chip_free() - Free the mux-chip for good. 1898f3addf1SPeter Rosin * @mux_chip: The mux-chip to free. 1908f3addf1SPeter Rosin * 1918f3addf1SPeter Rosin * mux_chip_free() reverses the effects of mux_chip_alloc(). 1928f3addf1SPeter Rosin */ 1938f3addf1SPeter Rosin void mux_chip_free(struct mux_chip *mux_chip) 1948f3addf1SPeter Rosin { 1958f3addf1SPeter Rosin if (!mux_chip) 1968f3addf1SPeter Rosin return; 1978f3addf1SPeter Rosin 1988f3addf1SPeter Rosin put_device(&mux_chip->dev); 1998f3addf1SPeter Rosin } 2008f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_chip_free); 2018f3addf1SPeter Rosin 2028f3addf1SPeter Rosin static void devm_mux_chip_release(struct device *dev, void *res) 2038f3addf1SPeter Rosin { 2048f3addf1SPeter Rosin struct mux_chip *mux_chip = *(struct mux_chip **)res; 2058f3addf1SPeter Rosin 2068f3addf1SPeter Rosin mux_chip_free(mux_chip); 2078f3addf1SPeter Rosin } 2088f3addf1SPeter Rosin 2098f3addf1SPeter Rosin /** 2108f3addf1SPeter Rosin * devm_mux_chip_alloc() - Resource-managed version of mux_chip_alloc(). 2118f3addf1SPeter Rosin * @dev: The parent device implementing the mux interface. 2128f3addf1SPeter Rosin * @controllers: The number of mux controllers to allocate for this chip. 2138f3addf1SPeter Rosin * @sizeof_priv: Size of extra memory area for private use by the caller. 2148f3addf1SPeter Rosin * 2158f3addf1SPeter Rosin * See mux_chip_alloc() for more details. 2168f3addf1SPeter Rosin * 2178f3addf1SPeter Rosin * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno. 2188f3addf1SPeter Rosin */ 2198f3addf1SPeter Rosin struct mux_chip *devm_mux_chip_alloc(struct device *dev, 2208f3addf1SPeter Rosin unsigned int controllers, 2218f3addf1SPeter Rosin size_t sizeof_priv) 2228f3addf1SPeter Rosin { 2238f3addf1SPeter Rosin struct mux_chip **ptr, *mux_chip; 2248f3addf1SPeter Rosin 2258f3addf1SPeter Rosin ptr = devres_alloc(devm_mux_chip_release, sizeof(*ptr), GFP_KERNEL); 2268f3addf1SPeter Rosin if (!ptr) 2278f3addf1SPeter Rosin return ERR_PTR(-ENOMEM); 2288f3addf1SPeter Rosin 2298f3addf1SPeter Rosin mux_chip = mux_chip_alloc(dev, controllers, sizeof_priv); 2308f3addf1SPeter Rosin if (IS_ERR(mux_chip)) { 2318f3addf1SPeter Rosin devres_free(ptr); 2328f3addf1SPeter Rosin return mux_chip; 2338f3addf1SPeter Rosin } 2348f3addf1SPeter Rosin 2358f3addf1SPeter Rosin *ptr = mux_chip; 2368f3addf1SPeter Rosin devres_add(dev, ptr); 2378f3addf1SPeter Rosin 2388f3addf1SPeter Rosin return mux_chip; 2398f3addf1SPeter Rosin } 2408f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(devm_mux_chip_alloc); 2418f3addf1SPeter Rosin 2428f3addf1SPeter Rosin static void devm_mux_chip_reg_release(struct device *dev, void *res) 2438f3addf1SPeter Rosin { 2448f3addf1SPeter Rosin struct mux_chip *mux_chip = *(struct mux_chip **)res; 2458f3addf1SPeter Rosin 2468f3addf1SPeter Rosin mux_chip_unregister(mux_chip); 2478f3addf1SPeter Rosin } 2488f3addf1SPeter Rosin 2498f3addf1SPeter Rosin /** 2508f3addf1SPeter Rosin * devm_mux_chip_register() - Resource-managed version mux_chip_register(). 2518f3addf1SPeter Rosin * @dev: The parent device implementing the mux interface. 2528f3addf1SPeter Rosin * @mux_chip: The mux-chip to register. 2538f3addf1SPeter Rosin * 2548f3addf1SPeter Rosin * See mux_chip_register() for more details. 2558f3addf1SPeter Rosin * 2568f3addf1SPeter Rosin * Return: Zero on success or a negative errno on error. 2578f3addf1SPeter Rosin */ 2588f3addf1SPeter Rosin int devm_mux_chip_register(struct device *dev, 2598f3addf1SPeter Rosin struct mux_chip *mux_chip) 2608f3addf1SPeter Rosin { 2618f3addf1SPeter Rosin struct mux_chip **ptr; 2628f3addf1SPeter Rosin int res; 2638f3addf1SPeter Rosin 2648f3addf1SPeter Rosin ptr = devres_alloc(devm_mux_chip_reg_release, sizeof(*ptr), GFP_KERNEL); 2658f3addf1SPeter Rosin if (!ptr) 2668f3addf1SPeter Rosin return -ENOMEM; 2678f3addf1SPeter Rosin 2688f3addf1SPeter Rosin res = mux_chip_register(mux_chip); 2698f3addf1SPeter Rosin if (res) { 2708f3addf1SPeter Rosin devres_free(ptr); 2718f3addf1SPeter Rosin return res; 2728f3addf1SPeter Rosin } 2738f3addf1SPeter Rosin 2748f3addf1SPeter Rosin *ptr = mux_chip; 2758f3addf1SPeter Rosin devres_add(dev, ptr); 2768f3addf1SPeter Rosin 2778f3addf1SPeter Rosin return res; 2788f3addf1SPeter Rosin } 2798f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(devm_mux_chip_register); 2808f3addf1SPeter Rosin 2818f3addf1SPeter Rosin /** 2828f3addf1SPeter Rosin * mux_control_states() - Query the number of multiplexer states. 2838f3addf1SPeter Rosin * @mux: The mux-control to query. 2848f3addf1SPeter Rosin * 2858f3addf1SPeter Rosin * Return: The number of multiplexer states. 2868f3addf1SPeter Rosin */ 2878f3addf1SPeter Rosin unsigned int mux_control_states(struct mux_control *mux) 2888f3addf1SPeter Rosin { 2898f3addf1SPeter Rosin return mux->states; 2908f3addf1SPeter Rosin } 2918f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_control_states); 2928f3addf1SPeter Rosin 2938f3addf1SPeter Rosin /* 2948f3addf1SPeter Rosin * The mux->lock must be down when calling this function. 2958f3addf1SPeter Rosin */ 2968f3addf1SPeter Rosin static int __mux_control_select(struct mux_control *mux, int state) 2978f3addf1SPeter Rosin { 2988f3addf1SPeter Rosin int ret; 2998f3addf1SPeter Rosin 3008f3addf1SPeter Rosin if (WARN_ON(state < 0 || state >= mux->states)) 3018f3addf1SPeter Rosin return -EINVAL; 3028f3addf1SPeter Rosin 3038f3addf1SPeter Rosin if (mux->cached_state == state) 3048f3addf1SPeter Rosin return 0; 3058f3addf1SPeter Rosin 3068f3addf1SPeter Rosin ret = mux_control_set(mux, state); 3078f3addf1SPeter Rosin if (ret >= 0) 3088f3addf1SPeter Rosin return 0; 3098f3addf1SPeter Rosin 3108f3addf1SPeter Rosin /* The mux update failed, try to revert if appropriate... */ 3118f3addf1SPeter Rosin if (mux->idle_state != MUX_IDLE_AS_IS) 3128f3addf1SPeter Rosin mux_control_set(mux, mux->idle_state); 3138f3addf1SPeter Rosin 3148f3addf1SPeter Rosin return ret; 3158f3addf1SPeter Rosin } 3168f3addf1SPeter Rosin 3178f3addf1SPeter Rosin /** 3188f3addf1SPeter Rosin * mux_control_select() - Select the given multiplexer state. 3198f3addf1SPeter Rosin * @mux: The mux-control to request a change of state from. 3208f3addf1SPeter Rosin * @state: The new requested state. 3218f3addf1SPeter Rosin * 3228f3addf1SPeter Rosin * On successfully selecting the mux-control state, it will be locked until 3238f3addf1SPeter Rosin * there is a call to mux_control_deselect(). If the mux-control is already 3248f3addf1SPeter Rosin * selected when mux_control_select() is called, the caller will be blocked 3258f3addf1SPeter Rosin * until mux_control_deselect() is called (by someone else). 3268f3addf1SPeter Rosin * 3278f3addf1SPeter Rosin * Therefore, make sure to call mux_control_deselect() when the operation is 3288f3addf1SPeter Rosin * complete and the mux-control is free for others to use, but do not call 3298f3addf1SPeter Rosin * mux_control_deselect() if mux_control_select() fails. 3308f3addf1SPeter Rosin * 3318f3addf1SPeter Rosin * Return: 0 when the mux-control state has the requested state or a negative 3328f3addf1SPeter Rosin * errno on error. 3338f3addf1SPeter Rosin */ 3348f3addf1SPeter Rosin int mux_control_select(struct mux_control *mux, unsigned int state) 3358f3addf1SPeter Rosin { 3368f3addf1SPeter Rosin int ret; 3378f3addf1SPeter Rosin 3388f3addf1SPeter Rosin ret = down_killable(&mux->lock); 3398f3addf1SPeter Rosin if (ret < 0) 3408f3addf1SPeter Rosin return ret; 3418f3addf1SPeter Rosin 3428f3addf1SPeter Rosin ret = __mux_control_select(mux, state); 3438f3addf1SPeter Rosin 3448f3addf1SPeter Rosin if (ret < 0) 3458f3addf1SPeter Rosin up(&mux->lock); 3468f3addf1SPeter Rosin 3478f3addf1SPeter Rosin return ret; 3488f3addf1SPeter Rosin } 3498f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_control_select); 3508f3addf1SPeter Rosin 3518f3addf1SPeter Rosin /** 3528f3addf1SPeter Rosin * mux_control_try_select() - Try to select the given multiplexer state. 3538f3addf1SPeter Rosin * @mux: The mux-control to request a change of state from. 3548f3addf1SPeter Rosin * @state: The new requested state. 3558f3addf1SPeter Rosin * 3568f3addf1SPeter Rosin * On successfully selecting the mux-control state, it will be locked until 3578f3addf1SPeter Rosin * mux_control_deselect() called. 3588f3addf1SPeter Rosin * 3598f3addf1SPeter Rosin * Therefore, make sure to call mux_control_deselect() when the operation is 3608f3addf1SPeter Rosin * complete and the mux-control is free for others to use, but do not call 3618f3addf1SPeter Rosin * mux_control_deselect() if mux_control_try_select() fails. 3628f3addf1SPeter Rosin * 3638f3addf1SPeter Rosin * Return: 0 when the mux-control state has the requested state or a negative 3648f3addf1SPeter Rosin * errno on error. Specifically -EBUSY if the mux-control is contended. 3658f3addf1SPeter Rosin */ 3668f3addf1SPeter Rosin int mux_control_try_select(struct mux_control *mux, unsigned int state) 3678f3addf1SPeter Rosin { 3688f3addf1SPeter Rosin int ret; 3698f3addf1SPeter Rosin 3708f3addf1SPeter Rosin if (down_trylock(&mux->lock)) 3718f3addf1SPeter Rosin return -EBUSY; 3728f3addf1SPeter Rosin 3738f3addf1SPeter Rosin ret = __mux_control_select(mux, state); 3748f3addf1SPeter Rosin 3758f3addf1SPeter Rosin if (ret < 0) 3768f3addf1SPeter Rosin up(&mux->lock); 3778f3addf1SPeter Rosin 3788f3addf1SPeter Rosin return ret; 3798f3addf1SPeter Rosin } 3808f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_control_try_select); 3818f3addf1SPeter Rosin 3828f3addf1SPeter Rosin /** 3838f3addf1SPeter Rosin * mux_control_deselect() - Deselect the previously selected multiplexer state. 3848f3addf1SPeter Rosin * @mux: The mux-control to deselect. 3858f3addf1SPeter Rosin * 3868f3addf1SPeter Rosin * It is required that a single call is made to mux_control_deselect() for 3878f3addf1SPeter Rosin * each and every successful call made to either of mux_control_select() or 3888f3addf1SPeter Rosin * mux_control_try_select(). 3898f3addf1SPeter Rosin * 3908f3addf1SPeter Rosin * Return: 0 on success and a negative errno on error. An error can only 3918f3addf1SPeter Rosin * occur if the mux has an idle state. Note that even if an error occurs, the 3928f3addf1SPeter Rosin * mux-control is unlocked and is thus free for the next access. 3938f3addf1SPeter Rosin */ 3948f3addf1SPeter Rosin int mux_control_deselect(struct mux_control *mux) 3958f3addf1SPeter Rosin { 3968f3addf1SPeter Rosin int ret = 0; 3978f3addf1SPeter Rosin 3988f3addf1SPeter Rosin if (mux->idle_state != MUX_IDLE_AS_IS && 3998f3addf1SPeter Rosin mux->idle_state != mux->cached_state) 4008f3addf1SPeter Rosin ret = mux_control_set(mux, mux->idle_state); 4018f3addf1SPeter Rosin 4028f3addf1SPeter Rosin up(&mux->lock); 4038f3addf1SPeter Rosin 4048f3addf1SPeter Rosin return ret; 4058f3addf1SPeter Rosin } 4068f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_control_deselect); 4078f3addf1SPeter Rosin 408aa1f10e8SHans de Goede /* Note this function returns a reference to the mux_chip dev. */ 4098f3addf1SPeter Rosin static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np) 4108f3addf1SPeter Rosin { 4118f3addf1SPeter Rosin struct device *dev; 4128f3addf1SPeter Rosin 413cfba5de9SSuzuki K Poulose dev = class_find_device_by_of_node(&mux_class, np); 4148f3addf1SPeter Rosin 4158f3addf1SPeter Rosin return dev ? to_mux_chip(dev) : NULL; 4168f3addf1SPeter Rosin } 4178f3addf1SPeter Rosin 4188f3addf1SPeter Rosin /** 4198f3addf1SPeter Rosin * mux_control_get() - Get the mux-control for a device. 4208f3addf1SPeter Rosin * @dev: The device that needs a mux-control. 4218f3addf1SPeter Rosin * @mux_name: The name identifying the mux-control. 4228f3addf1SPeter Rosin * 4238f3addf1SPeter Rosin * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno. 4248f3addf1SPeter Rosin */ 4258f3addf1SPeter Rosin struct mux_control *mux_control_get(struct device *dev, const char *mux_name) 4268f3addf1SPeter Rosin { 4278f3addf1SPeter Rosin struct device_node *np = dev->of_node; 4288f3addf1SPeter Rosin struct of_phandle_args args; 4298f3addf1SPeter Rosin struct mux_chip *mux_chip; 4308f3addf1SPeter Rosin unsigned int controller; 4318f3addf1SPeter Rosin int index = 0; 4328f3addf1SPeter Rosin int ret; 4338f3addf1SPeter Rosin 4348f3addf1SPeter Rosin if (mux_name) { 4358f3addf1SPeter Rosin index = of_property_match_string(np, "mux-control-names", 4368f3addf1SPeter Rosin mux_name); 4378f3addf1SPeter Rosin if (index < 0) { 4388f3addf1SPeter Rosin dev_err(dev, "mux controller '%s' not found\n", 4398f3addf1SPeter Rosin mux_name); 4408f3addf1SPeter Rosin return ERR_PTR(index); 4418f3addf1SPeter Rosin } 4428f3addf1SPeter Rosin } 4438f3addf1SPeter Rosin 4448f3addf1SPeter Rosin ret = of_parse_phandle_with_args(np, 4458f3addf1SPeter Rosin "mux-controls", "#mux-control-cells", 4468f3addf1SPeter Rosin index, &args); 4478f3addf1SPeter Rosin if (ret) { 4488f3addf1SPeter Rosin dev_err(dev, "%pOF: failed to get mux-control %s(%i)\n", 4498f3addf1SPeter Rosin np, mux_name ?: "", index); 4508f3addf1SPeter Rosin return ERR_PTR(ret); 4518f3addf1SPeter Rosin } 4528f3addf1SPeter Rosin 4538f3addf1SPeter Rosin mux_chip = of_find_mux_chip_by_node(args.np); 4548f3addf1SPeter Rosin of_node_put(args.np); 4558f3addf1SPeter Rosin if (!mux_chip) 4568f3addf1SPeter Rosin return ERR_PTR(-EPROBE_DEFER); 4578f3addf1SPeter Rosin 4588f3addf1SPeter Rosin if (args.args_count > 1 || 4598f3addf1SPeter Rosin (!args.args_count && (mux_chip->controllers > 1))) { 4608f3addf1SPeter Rosin dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n", 4618f3addf1SPeter Rosin np, args.np); 462aa1f10e8SHans de Goede put_device(&mux_chip->dev); 4638f3addf1SPeter Rosin return ERR_PTR(-EINVAL); 4648f3addf1SPeter Rosin } 4658f3addf1SPeter Rosin 4668f3addf1SPeter Rosin controller = 0; 4678f3addf1SPeter Rosin if (args.args_count) 4688f3addf1SPeter Rosin controller = args.args[0]; 4698f3addf1SPeter Rosin 4708f3addf1SPeter Rosin if (controller >= mux_chip->controllers) { 4718f3addf1SPeter Rosin dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n", 4728f3addf1SPeter Rosin np, controller, args.np); 473aa1f10e8SHans de Goede put_device(&mux_chip->dev); 4748f3addf1SPeter Rosin return ERR_PTR(-EINVAL); 4758f3addf1SPeter Rosin } 4768f3addf1SPeter Rosin 4778f3addf1SPeter Rosin return &mux_chip->mux[controller]; 4788f3addf1SPeter Rosin } 4798f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_control_get); 4808f3addf1SPeter Rosin 4818f3addf1SPeter Rosin /** 4828f3addf1SPeter Rosin * mux_control_put() - Put away the mux-control for good. 4838f3addf1SPeter Rosin * @mux: The mux-control to put away. 4848f3addf1SPeter Rosin * 4858f3addf1SPeter Rosin * mux_control_put() reverses the effects of mux_control_get(). 4868f3addf1SPeter Rosin */ 4878f3addf1SPeter Rosin void mux_control_put(struct mux_control *mux) 4888f3addf1SPeter Rosin { 4898f3addf1SPeter Rosin put_device(&mux->chip->dev); 4908f3addf1SPeter Rosin } 4918f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(mux_control_put); 4928f3addf1SPeter Rosin 4938f3addf1SPeter Rosin static void devm_mux_control_release(struct device *dev, void *res) 4948f3addf1SPeter Rosin { 4958f3addf1SPeter Rosin struct mux_control *mux = *(struct mux_control **)res; 4968f3addf1SPeter Rosin 4978f3addf1SPeter Rosin mux_control_put(mux); 4988f3addf1SPeter Rosin } 4998f3addf1SPeter Rosin 5008f3addf1SPeter Rosin /** 5018f3addf1SPeter Rosin * devm_mux_control_get() - Get the mux-control for a device, with resource 5028f3addf1SPeter Rosin * management. 5038f3addf1SPeter Rosin * @dev: The device that needs a mux-control. 5048f3addf1SPeter Rosin * @mux_name: The name identifying the mux-control. 5058f3addf1SPeter Rosin * 5068f3addf1SPeter Rosin * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno. 5078f3addf1SPeter Rosin */ 5088f3addf1SPeter Rosin struct mux_control *devm_mux_control_get(struct device *dev, 5098f3addf1SPeter Rosin const char *mux_name) 5108f3addf1SPeter Rosin { 5118f3addf1SPeter Rosin struct mux_control **ptr, *mux; 5128f3addf1SPeter Rosin 5138f3addf1SPeter Rosin ptr = devres_alloc(devm_mux_control_release, sizeof(*ptr), GFP_KERNEL); 5148f3addf1SPeter Rosin if (!ptr) 5158f3addf1SPeter Rosin return ERR_PTR(-ENOMEM); 5168f3addf1SPeter Rosin 5178f3addf1SPeter Rosin mux = mux_control_get(dev, mux_name); 5188f3addf1SPeter Rosin if (IS_ERR(mux)) { 5198f3addf1SPeter Rosin devres_free(ptr); 5208f3addf1SPeter Rosin return mux; 5218f3addf1SPeter Rosin } 5228f3addf1SPeter Rosin 5238f3addf1SPeter Rosin *ptr = mux; 5248f3addf1SPeter Rosin devres_add(dev, ptr); 5258f3addf1SPeter Rosin 5268f3addf1SPeter Rosin return mux; 5278f3addf1SPeter Rosin } 5288f3addf1SPeter Rosin EXPORT_SYMBOL_GPL(devm_mux_control_get); 5298f3addf1SPeter Rosin 5308f3addf1SPeter Rosin /* 5318f3addf1SPeter Rosin * Using subsys_initcall instead of module_init here to try to ensure - for 5328f3addf1SPeter Rosin * the non-modular case - that the subsystem is initialized when mux consumers 5338f3addf1SPeter Rosin * and mux controllers start to use it. 5348f3addf1SPeter Rosin * For the modular case, the ordering is ensured with module dependencies. 5358f3addf1SPeter Rosin */ 5368f3addf1SPeter Rosin subsys_initcall(mux_init); 5378f3addf1SPeter Rosin module_exit(mux_exit); 5388f3addf1SPeter Rosin 5398f3addf1SPeter Rosin MODULE_DESCRIPTION("Multiplexer subsystem"); 5408f3addf1SPeter Rosin MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 5418f3addf1SPeter Rosin MODULE_LICENSE("GPL v2"); 542